It is proposed to carry out precision neutron diffraction crystal structure analysis on important mono- and di-saccharides. A neutron analysis of beta-maltose monohydrate, currently in progress, will be completed. Obtaining crystals of adequate dimensions for neutron diffraction has been difficult. We therefore plan to improve our crystal growing methods to solve this problem. The structures of melibiose and stachyose pentahydrate were determined from X-ray diffraction data and the refinement of these structures will be completed. X-ray diffraction will also be used to investigate the structure of an alpha, beta-maltose complex. A new attempt to solve the structure of cycloheptaamylose hydrate is planned using some recently developed interpretative methods. Collaboration with Professor J. Pople on quantum mechanical calculations relating to the anomeric effect will continue. Collaboration with Dr. Marshall Newton on a theoretical interpretation of the planarity of alpha-hydroxy carboxylic acids is planned. The computer programs, which have been put into operation for conformational analysis and packing analysis, will be applied to some known oligosaccharide structures. X-ray structure determinations are planned for some anhydro fused ring compounds believed to have pyranose rings in the boat conformation. BIBLIOGRAPHIC REFERENCES: The Crystal Structures of the A and B Forms of Potassium D-Gluconate Monohydrate by Neutron Diffraction; N.C. Panagiotopoulos, G.A. Jeffrey, S. La Placa and W.C. Hamilton Acta Cryst. B30, 1421-1430 (1974).